Summary Report No. 40

SANA
(‘Sanierung der Atmosphäre über den neuen Bundensländern’) was a joint
scientific programme to assess tropospheric processes and ecological
impacts under the rapid change of air pollution emission in the former
GDR (East Germany) since the late ‘80s. It was applied for after the
German reunification in 1990 and first investigations started shortly
thereafter. The main investigations took place during the years 1993 to
1995.

The Potsdam Institute for Climate Impact Research was responsible
for co-ordinating the activities of the ecological investigations
within this programme. Furthermore, the modelling of ecological impacts
was executed by PIK scientists on the basis of ecological
investigations, mainly executed by the Centre of Agricultural Landscape
and Land Use Science (ZALF), and the Technical University in Cottbus
(BTUC). The modelling task included the representation of physical,
chemical and physiological processes in Scots Pine (Pinus sylv. L.) forests as well as the
extrapolation of the results to the regional level, considering different air pollution and climate scenarios.

This report includes the final project results of the two groups at
PIK, involved in the project: Firstly, the newly developed
physiologically-based forest growth model FORSANA was applied for the
first time to three pine stands, which differed largely in their air
pollution and deposition history. (The evaluation of the model is
presented in PIK Report 32). The model was able to explain the growth
during the last decades of at least two of the three stands from the
climatic and deposition conditions at the sites. The third site was
shown to be exceptional with respect to its relation between dimension
and age, and was supposed to be exposed to major disturbances in the
past, which could not be accounted for by the model.

To extrapolate from the stand level to the regional level, FORSANA
was initialised with spatially explicit data from forestry inventory
and soil maps. Simulations were executed with measured weather records
and regional distributions of deposition and air pollution, which were
estimated on the basis of emission inventories and wind directions.
Different assumptions about the development of air pollution had been
applied to investigate different pollution abatement strategies. The
results showed that a positive effect can be expected from the actual
emission reductions close the main centres of emission, but showed also
that this effect is decreasing with increasing distance from the
emission source.

Two additional papers are presented in this report, to give a more
detailed insight in the history and aims of the joint project, and to
present an overview of the integrated results of the ecological
investigations.

All four presented papers are submitted to the journal ‘Nutrients in
ecosystems’, which shall be part of a special edition, presenting
results from all ecological investigations within the SANA project,
including modelling results.

Bellmann, K., Grote, R.: The History of SANA - Introduction to the Project